EP0541321A2 - Générateur d'horloge vidéo pour dispositif de balayage optique d'image - Google Patents

Générateur d'horloge vidéo pour dispositif de balayage optique d'image Download PDF

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Publication number
EP0541321A2
EP0541321A2 EP19920310037 EP92310037A EP0541321A2 EP 0541321 A2 EP0541321 A2 EP 0541321A2 EP 19920310037 EP19920310037 EP 19920310037 EP 92310037 A EP92310037 A EP 92310037A EP 0541321 A2 EP0541321 A2 EP 0541321A2
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EP
European Patent Office
Prior art keywords
clock signal
linear scale
scanner
video clock
light
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP19920310037
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German (de)
English (en)
Other versions
EP0541321B1 (fr
EP0541321A3 (en
Inventor
Yoshinori Kuroiwa
Hiroshi Nishida
Hisashi Okugawa
Yutaka Ichihara
Satoru Kumagai
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Nikon Corp
Original Assignee
Nikon Corp
Nippon Kogaku KK
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from JP3291723A external-priority patent/JPH05127109A/ja
Priority claimed from JP03291724A external-priority patent/JP3111551B2/ja
Priority claimed from JP3295944A external-priority patent/JPH05136954A/ja
Application filed by Nikon Corp, Nippon Kogaku KK filed Critical Nikon Corp
Priority to EP96113812A priority Critical patent/EP0748098A3/fr
Publication of EP0541321A2 publication Critical patent/EP0541321A2/fr
Publication of EP0541321A3 publication Critical patent/EP0541321A3/en
Application granted granted Critical
Publication of EP0541321B1 publication Critical patent/EP0541321B1/fr
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
    • H04N1/024—Details of scanning heads ; Means for illuminating the original
    • H04N1/028—Details of scanning heads ; Means for illuminating the original for picture information pick-up
    • H04N1/02815—Means for illuminating the original, not specific to a particular type of pick-up head
    • H04N1/0282—Using a single or a few point light sources, e.g. a laser diode
    • H04N1/0283—Using a single or a few point light sources, e.g. a laser diode in combination with a light deflecting element, e.g. a rotating mirror
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
    • H04N1/04—Scanning arrangements, i.e. arrangements for the displacement of active reading or reproducing elements relative to the original or reproducing medium, or vice versa
    • H04N1/0402—Scanning different formats; Scanning with different densities of dots per unit length, e.g. different numbers of dots per inch (dpi); Conversion of scanning standards
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
    • H04N1/04—Scanning arrangements, i.e. arrangements for the displacement of active reading or reproducing elements relative to the original or reproducing medium, or vice versa
    • H04N1/0402—Scanning different formats; Scanning with different densities of dots per unit length, e.g. different numbers of dots per inch (dpi); Conversion of scanning standards
    • H04N1/0408—Different densities of dots per unit length
    • H04N1/0411—Different densities of dots per unit length in the main scanning direction
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
    • H04N1/04—Scanning arrangements, i.e. arrangements for the displacement of active reading or reproducing elements relative to the original or reproducing medium, or vice versa
    • H04N1/0402—Scanning different formats; Scanning with different densities of dots per unit length, e.g. different numbers of dots per inch (dpi); Conversion of scanning standards
    • H04N1/042—Details of the method used
    • H04N1/0426—Details of the method used using different sized scanning elements, e.g. reproducing different sized dots
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
    • H04N1/04—Scanning arrangements, i.e. arrangements for the displacement of active reading or reproducing elements relative to the original or reproducing medium, or vice versa
    • H04N1/0402—Scanning different formats; Scanning with different densities of dots per unit length, e.g. different numbers of dots per inch (dpi); Conversion of scanning standards
    • H04N1/042—Details of the method used
    • H04N1/0446—Varying the modulation time or intensity
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
    • H04N1/04—Scanning arrangements, i.e. arrangements for the displacement of active reading or reproducing elements relative to the original or reproducing medium, or vice versa
    • H04N1/0402—Scanning different formats; Scanning with different densities of dots per unit length, e.g. different numbers of dots per inch (dpi); Conversion of scanning standards
    • H04N1/042—Details of the method used
    • H04N1/0449—Details of the method used using different sets of scanning elements, e.g. for different formats
    • H04N1/0452—Details of the method used using different sets of scanning elements, e.g. for different formats mounted on the same support or substrate
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
    • H04N1/04—Scanning arrangements, i.e. arrangements for the displacement of active reading or reproducing elements relative to the original or reproducing medium, or vice versa
    • H04N1/047—Detection, control or error compensation of scanning velocity or position
    • H04N1/053—Detection, control or error compensation of scanning velocity or position in main scanning direction, e.g. synchronisation of line start or picture elements in a line
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
    • H04N1/04—Scanning arrangements, i.e. arrangements for the displacement of active reading or reproducing elements relative to the original or reproducing medium, or vice versa
    • H04N1/113—Scanning arrangements, i.e. arrangements for the displacement of active reading or reproducing elements relative to the original or reproducing medium, or vice versa using oscillating or rotating mirrors
    • H04N1/1135—Scanning arrangements, i.e. arrangements for the displacement of active reading or reproducing elements relative to the original or reproducing medium, or vice versa using oscillating or rotating mirrors for the main-scan only
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N2201/00—Indexing scheme relating to scanning, transmission or reproduction of documents or the like, and to details thereof
    • H04N2201/024—Indexing scheme relating to scanning, transmission or reproduction of documents or the like, and to details thereof deleted
    • H04N2201/02406—Arrangements for positioning elements within a head
    • H04N2201/02439—Positioning method
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N2201/00—Indexing scheme relating to scanning, transmission or reproduction of documents or the like, and to details thereof
    • H04N2201/04—Scanning arrangements
    • H04N2201/047—Detection, control or error compensation of scanning velocity or position
    • H04N2201/04701—Detection of scanning velocity or position
    • H04N2201/0471—Detection of scanning velocity or position using dedicated detectors
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N2201/00—Indexing scheme relating to scanning, transmission or reproduction of documents or the like, and to details thereof
    • H04N2201/04—Scanning arrangements
    • H04N2201/047—Detection, control or error compensation of scanning velocity or position
    • H04N2201/04701—Detection of scanning velocity or position
    • H04N2201/04734—Detecting at frequent intervals, e.g. once per line for sub-scan control
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N2201/00—Indexing scheme relating to scanning, transmission or reproduction of documents or the like, and to details thereof
    • H04N2201/04—Scanning arrangements
    • H04N2201/047—Detection, control or error compensation of scanning velocity or position
    • H04N2201/04701—Detection of scanning velocity or position
    • H04N2201/04744—Detection of scanning velocity or position by detecting the scanned beam or a reference beam
    • H04N2201/04746—Detection of scanning velocity or position by detecting the scanned beam or a reference beam after modulation by a grating, mask or the like
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N2201/00—Indexing scheme relating to scanning, transmission or reproduction of documents or the like, and to details thereof
    • H04N2201/04—Scanning arrangements
    • H04N2201/047—Detection, control or error compensation of scanning velocity or position
    • H04N2201/04753—Control or error compensation of scanning position or velocity
    • H04N2201/04755—Control or error compensation of scanning position or velocity by controlling the position or movement of a scanning element or carriage, e.g. of a polygonal mirror, of a drive motor
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N2201/00—Indexing scheme relating to scanning, transmission or reproduction of documents or the like, and to details thereof
    • H04N2201/04—Scanning arrangements
    • H04N2201/047—Detection, control or error compensation of scanning velocity or position
    • H04N2201/04753—Control or error compensation of scanning position or velocity
    • H04N2201/04758—Control or error compensation of scanning position or velocity by controlling the position of the scanned image area
    • H04N2201/04767—Control or error compensation of scanning position or velocity by controlling the position of the scanned image area by controlling the timing of the signals, e.g. by controlling the frequency o phase of the pixel clock
    • H04N2201/04768—Controlling the frequency of the signals
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N2201/00—Indexing scheme relating to scanning, transmission or reproduction of documents or the like, and to details thereof
    • H04N2201/04—Scanning arrangements
    • H04N2201/047—Detection, control or error compensation of scanning velocity or position
    • H04N2201/04753—Control or error compensation of scanning position or velocity
    • H04N2201/04794—Varying the control or compensation during the scan, e.g. using continuous feedback or from line to line

Definitions

  • the present invention relates to a video clock signal generator which receives a light emitted from a light source by a linear scale through a vibration scanner, detects a light reflected by or transmitted through a grating of the linear scale and processes an output signal thereof to generate a clock pulse, and more particularly to a video clock signal generator in an optical scan type image input device such as a laser scan microscope which scans a light irradiated to a sample and senses a reflected light, a transmitted light or a fluorescent light from the sample in accordance with a position of the light to form an image.
  • an optical scan type image input device such as a laser scan microscope which scans a light irradiated to a sample and senses a reflected light, a transmitted light or a fluorescent light from the sample in accordance with a position of the light to form an image.
  • An optical scan type image input device disclosed in U.S. Patent 4,212,018 generates a video clock signal by using a linear scale. It is easy to realize and hard to be affected by disturbance.
  • a laser beam from a laser light source is focused and reflected by a mirror surface of a scanner, and the reflected light is directed onto a linear scale as a scanning light spot by the rotation of the scanner.
  • the light spot is scanned to cross a grating of the linear scale. Since it crosses the grating as it is scanned, an intensity of the laser beam transmitting through the linear scale varies.
  • the modulated laser beam is converted to a modulated signal by a photo-sensor and the modulated signal is comparated at an appropriate level so that a video clock signal is generated in accordance with the rotation of the scanner.
  • the prior art discloses the scanner which uses a polygon mirror although a scanner which reciprocally scans a light spot on a linear scale such as a galvanometer or a resonance type galvanometer (resonant mirror which vibrates at its resonance frequency) is also known.
  • the resonant mirror is effective for the image input by high speed scan because of its high vibration frequency.
  • the resonance frequency varies by the affect of change in an environment such as a temperature, an amplitude is not stable even if an input frequency is constant, and it is difficult to form an ideal image.
  • the size of the linear scale may be doubled and a focal distance of a focusing lens may be elongated to double the amplitude of the light spot.
  • a pitch of the grating of the linear scale may be reduced to one half and a diameter of the light spot may be reduced to one half.
  • the focal distance of the focusing lens is elongated, the diameter of the light spot on the linear scale increases and a light spot which is small enough to the pitch of the grating cannot be attained. Same is true when the pitch of the grating is reduced to one half.
  • the frequency of the amplified photo-sensor output is multiplied by a PLL (phase-locked loop) circuit, and it is supplied to a comparator to generate a required number of clock signals.
  • the number of video clock signals may be increased by increasing the frequency multiplication factor by the PLL circuit.
  • the amplitude of the scanner and the scan velocity are constant, an enlarged image may be formed by this method.
  • it is necessary to use a high speed IC for the PLL circuit and even with such a high speed IC, the circuit may not be compatible with a high frequency or the configuration of the PLL circuit is complex. As a result, it is not easy to attain an enlarged image.
  • the optical scan type image input device of the present invention comprises a linear scale (or a mask having opposite ends thereof spaced by a predetermined distance), a reciprocating vibration scanner mirror for reflecting a laser beam from a light source to form a vibrating light spot on the linear scale, a detector for generating an output signal representing light information from the linear scale, a counter for counting a time required for the light spot to reach from one end of the linear scale to the other end in accordance with the output signal of the detector, and means for controlling an amplitude of the scanner in accordance with the reach time.
  • the reach time is compared with a predetermined reference time and the amplitude of the scanner is adjusted until they reach a predetermined relation.
  • the controlled amplitude may be easily altered.
  • a resonance type galvanometer which is driven by a sine wave is used as the scanner.
  • the image input device of the present invention comprises a scanner for scanning a laser beam from a light source, a linear scale arranged in an optical path of the laser beam scanned by the scanner, a first optical member arranged in an optical path between the light source and the linear scale for forming two light spots of different optical characteristics on the linear scale, a second optical member for separating the light information from the two light spots into two laser beams in accordance with the optical characteristics, two photo-sensors for sensing the two laser beams separated by the second optical means and a processing circuit for generating clock signals in accordance with the output signals of the photo-sensors.
  • a center of the two light spots is shifted by one quarter of the pitch of the grating perpendicularly to the grating of the linear scale (along a scan direction).
  • the processing circuit generates the clock signals based on the output signals of the two photo-sensors, and a sum signal and a difference signal thereof. Thus, signals which are phase-shifted by 1/8 period with respect to the output signals of the photo-sensors are generated.
  • two light beams which are separable by the difference in polarization characteristic or two light beams which are separable by the difference in wavelength are used as the two light spots.
  • the image input device of the present invention comprises a scanner for scanning a sample, and a plurality of types of linear scales selectively arranged in an optical path of a laser beam scanned by the scanner.
  • the plurality of types of linear scales differ from each other in the length of range in which the grating is formed (scale length).
  • the device further comprises means for selecting one of the plurality of types of linear scales and means for changing an amplitude of the vibration scanner to cope with the scale length of the selected linear scale.
  • the range of scan of the sample of the scanner is narrowed and the range of scan of the laser beam directd to the linear scale is narrowed in synchronism therewith.
  • the plurality of types of linear scales are attained by providing a plurality of scale patterns having different scale lengths on a scale base plate.
  • the plurality of types of linear scales are attained by providing a scale pattern having a continuously changing scale length so that a pitch of the grating gradually changes, on a scale base plate.
  • the linear scales of various types may have the same pitch of grating irrespective of the scale length, or the pitch of the grating may be changed in accordance with the scale length.
  • magnification factor can be very readily altered.
  • Fig. 1 shows an embodiment of a laser scanned microscope.
  • a laser beam from a laser light source 2 is reflected by a mirror 3 and a vibration scanner 5 and it is focused by a lens 4 to form a vibrating light spot on a sample 1.
  • a reflected light and a fluorescent light from the sample 1 are directed back to the lens 4, the vibration scanner 5 and the mirror 3, reflected by a beam splitter 6 and directed to a detector 7, which produces an image signal.
  • An optical system including the elements 2 - 7 forms a confocal optical system.
  • the vibration scanner 5 is a resonant mirror which resonates by a sine wave at a resonance frequency.
  • the scanner 5 has reflection planes on both planes thereof and is rotated around a rotation angle which is normal to a plane of the drawing.
  • Another laser light source 8 for emitting a laser beam LB to the scanner 5 is provided.
  • the laser beam LB reflected by the scanner 5 is focused on a screen mask 9 as a light spot which vibrates in synchronism with the light spot on the sample 1.
  • the laser beam LB transmitted through the screen mask 9 is detected by a detector 10, and a detection signal of the detector 10 is applied to a control circuit 11 for processing.
  • the control circuit 11 comprises a sine wave generator 12 for generating a sine wave at a resonance frequency of the scanner 5, a variable amplification factor amplifier 13 for controlling the amplitude of the sine wave, an actuator 14 for driving the scanner 5, an interval counter 15 for counting an output interval of the detection signal from the detector 10, and a controller 16 for controlling the amplification factor of the amplifier 13 in response to the output of the interval counter 15.
  • a reference time generator 17 generates a reference time output which can be varied by an input device 18.
  • the screen mask 9 is a transparent plate which has a screen area 9a of a predetermined length extending laterally at the center and light transmission areas 9b on both sides.
  • the vibrating spot light SP by the laser beam LB reciprocates between points a1 and a2 which are located in the light transmission areas 9b beyond the opposite ends of the screen area 9a.
  • the sine wave amplified by the amplifier 13 is supplied to the actuator 14, which vibrates the vibration scanner 5 by the sine wave.
  • the laser beam from the laser light source 2 forms a light spot which reciprocates on the sample 1 parallelly to the plane of the drawing.
  • the light energy generated from the sample by the irradiation of the laser beam to the sample 1 is directed to the detector 7 through the mirrors 5, 3 and 6, and an image of the sample is generated by the processing unit, not shown.
  • the laser beam LB from the laser light source 8 forms the light spot SP which reciprocates on the screen mask 9 parallelly to the plane of the drawing of Fig. 1.
  • the laser beam LB reaches the detector 10 only when the light spot SP is on the light transmission area 9b beyond the screen area 9a of the mask 9.
  • the detector 10 produces an output signal as shown in Fig. 5, in which two peaks b1 and b2 of the signal correspond to the points a1 and a2 of Fig. 3.
  • the output signal of the detector 10 is binarized by a slice level Ref and it is supplied to the interval counter 15 which counts the time interval between the two peaks b1 and b2. Since the drive frequency of the vibration mirror 5 is constant, the time interval is reduced as the amplitude of the vibration mirror 5 is increased, and is increased when the amplitude of the mirror is decreased.
  • the controller 16 compares the output interval of the detection signal counted by the interval counter 15 with the exact reference time from the reference time generator 17 and supplies an amplification factor feedback signal to the amplifier 13, which controls the amplification factor in accordance with the feedback signal from the controller 16. As a result, the amplitude of the mirror 5 is controlled such that the time interval of the two peaks b1 and b2 of the output signal is always kept constant.
  • the mask 9 is replaced by another mask having a different size of the screen area, and the reference time is altered by the input device 18.
  • FIG. 4 A modification of the screen mask which uses a linear mask is shown in Fig. 4.
  • a video clock signal to be used for the A/D conversion of the image information of the laser scanned microscope produced by the detector 7 can be generated.
  • the screen mask 19 is a linear scale having a number of screen areas 19a formed at a predetermined pitch along the direction of movement of the light spot.
  • the light spot SP of the laser beam LB vibrates between outermost points C1 and C2 of the area in which the screen area is formed.
  • the output signal of the detector 10 produced through the screen mask 19 is shown in Fig. 6.
  • Two peaks d1 and d2 are generated to correspond to the points C1 and C2, and a number of peaks e are generated between the two peaks to correspond to the pitch of the linear scale.
  • the two peaks are binarized by a slice level Ref 1 and it is used for the amplitude control of the vibration mirror.
  • the peaks e are binarized by a slice level Ref 2 and it is used as a video clock signal to be used for the A/D conversion of the image information.
  • the light transmission area of the screen mask may be replaced by a reflection area and a reflected light from the mask may be detected.
  • a reflected mirror may be detected by using the same mask as that of the embodiment, or the screen area and the light transmission area may be arranged oppositely and the transmitted signal may be detected.
  • Fig. 7 shows a video clock signal generator.
  • a vibration scanner 23 is arranged to face a laser light source 21 which may be a semiconductor laser unit, and a transmission type linear scale 25 is arranged within an area of the amplitude of the laser beam emitted from the scanner 23.
  • a first optical member 22 is arranged between the laser light source 21 and the scanner 23 so that two light spots of different optical characteristics are formed on the linear scale 25 from the laser beam emitted from the laser light source 21.
  • the first optical member 22 is one which separates the laser beams by the difference in the optical characteristic and direct them in different directions such as a double refraction element which splits a beam by a polarization characteristic, for example, a Wollaston prism or a Nomarski prism.
  • the scanner 23 may be a resonant mirror or a polygon mirror, or it may be a galvanometer.
  • a condenser lens 24 for focusing the laser beam onto the linear scale 25 is arranged in front of the linear scale 25.
  • the spacing between the gratings of the linear scale 25 is equal to the pitch L while the spacing between the two light spots A and B formed on the linear scale 25 by the condenser lens 24 is equal to L/4. Namely, the centers of the two light spots A and B are shifted by one quarter of the pitch in the direction of array of the grating of the linear scale 25 (in the direction of pitch).
  • a second optical member 27 arranged behind the linear scale 25 through a focusing lens 26 separates the two beams transmitted through the linear scale 25 based on the difference in the optical characteristic.
  • the second optical member 27 may be a polarization beam splitter which transmits one of the two beams which form the light spots A and B and reflects the other.
  • Two photo-sensors 28 and 29 are arranged to sense the two beams separated by the second optical member 27.
  • a processing circuit 40 generates a clock signal based on the output signals of the photo-sensors 28 and 29, and a sum signal and a difference signal thereof.
  • the processing circuit 40 comprises I/V conversion amplifiers 41 and 42 for receiving electrical output signals C and D from the two photo-sensors 28 and 29, a summing amplifier 43 for summing the outputs of the I/V conversion amplifiers 41 and 42 to produce a sum signal, a differential amplifier 44 for differentiating the output to produce a differential signal, comparators 45 - 48 for forming clock signals from the outputs of the I/V conversion amplifiers 41 and 42 and the outputs of the amplifiers 43 and 44, and clock varying switches 49 and 50.
  • the laser beam emitted from the laser light source 21 is split into two beams of different polarization directions by the first optical member 22, and they are directed to the scanner 23.
  • the scanner 23 vibrates the two beams and directs them toward the linear scale 25.
  • the two directed beams are focused by the condenser lens 24 so that the two light spots A and B of the different optical characteristics are formed on the linear scale 25.
  • the two light spots A and B are scanned to cross the grating of the linear scale 25 by the scanner 23.
  • the two laser beams which were intensity-modulated by the linear scale 25 are directed to the second optical member 27 where they are separated by the polarization.
  • the beam which forms the light spot A is transmitted through the second optical member 27 and the beam which forms the light spot B is reflected.
  • Both beams are directed to the two photo-sensors 28 and 29, respectively, and are photo-electrically converted to the output signals C and D, which are supplied to the processing circuit 40.
  • the output signals C and D have a phase shift of ⁇ /2 from each other as shown in Fig. 10.
  • the two output signals C and D are applied to the I/V amplifiers 41 and 42 of the processing circuit 40 for the I/V conversion, and the outputs therefrom are compared by the comparators 45 and 46 with an appropriate level so that equi-interval clock signals f1, f2,... which are double in number compared with those produced by one light spot are produced.
  • the two output signals C and D are combined by the summing amplifier 43 to produce the sum signal F, and combined by the differential amplifier 44 to produce the differential signal G. They are shifted in phase by 1/8 period with respect to the two output signals C and D, respectively, so that further clock signals g1, g2,... are produced.
  • the output clock signals may be controlled. By using a known insertion method, more number of clock signals can be generated.
  • the video clock signal generator may be configured as shown in Fig. 11.
  • a vibration scanner 54 is arranged to face the laser light source 51, and the laser beam emitted from the scanner 54 is focused onto a reflection type linear scale 56 by a focusing lens 55.
  • a first optical member 53 for forming two light spots A1 and B1 of different optical characteristics are arranged between the laser light source 51 and the scanner 54. Like in the embodiment of Fig. 7, centers of the two light spots A1 and B1 are shifted by one quarter of the pitch in the direction of array of the grating of the linear scale 56 (in the direction of pitch).
  • the scanner 54 and the linear scale 56 are arranged at conjugate positions to the focusing lens 55.
  • the laser beam reflected by the surface of the linear scale 56 is directed back along the substantially same optical path, reflected by the beam splitter 52 and separated by a second optical member 57.
  • Two photo-sensors 58 and 59 are mounted on the second optical member 57 to sense the two separated signals.
  • the output signals of the two photo-sensors 58 and 59 are processed by the processing circuit 40 as they are in the embodiment of Fig. 7.
  • FIG. 12 shows a schematic configuration of a scanning microscope and the like elements to those shown in Fig. 1 are designated by the like numerals and the explanation thereof is omitted.
  • a construction and an operation of the video clock signal generator 60 are explained below in detail.
  • a laser beam LB from a laser light source 8 is reflected by a vibration scanner 5 and focused to a light spot SP which vibrates on a linear scale 70.
  • the linear scale 70 is formed by a circular transparent plate 71 on which four patterns 72 to 75 are circumferentially spaced from each other.
  • the four patterns 72 to 75 have different widths of areas in which the gratings are formed. Assuming that the width of the pattern 72 is 1, the widths of the patterns 73 to 75 change stepwise to 1/2, 1/4 and 1/8, respectively.
  • the numbers of gratings of the four patterns 72 to 75 are equal. Accordingly, assuming that the pitch of the grating of the pattern 72 is "1", the pitches of the gratings of the patterns 73 to 75 change stepwise to 1/2, 1/4 and 1/8, respectively.
  • an actuator 61 for rotating the linear scale 70 to face the patterns 73 to 75 to the light spot SP, and a detector 62 for detecting the rotation position of the linear scale 70 are provided.
  • a detection circuit 63 is connected to the detector 62.
  • the detection circuit 63 is connected to an actuator 14 through a CPU 64 and an amplitude control circuit 65 for controlling the amplitude of the vibration scanner 5.
  • An amplifier 66 for amplifying a detection signal is connected to a detector 10 which detects the laser beam LB transmitted through the grating of the linear scale 70, and a comparator 67 is connected to the amplifier 66.
  • the laser beam LB reflected by the surface of the vibration scanner 5 forms a light spot on the linear scale 70.
  • the rotation position of the linear scale 70 is set such that the pattern 72 is positioned on the optical axis
  • the light spot SP is scanned on the pattern 72 in a direction of solid line arrow in Fig. 13.
  • the laser beam LB transmitted through the pattern 72 is detected by the detector 10.
  • the detection signal of the detector 10 is amplified by the amplifier 66 and applied to the comparator 67 where it is converted to clock signals which correspond to the number of gratings of the pattern 72.
  • the sample 1 is scanned by the laser beam from the laser light source 2 through the vibration scanner 5.
  • the scan of the sample 1 is in synchronism with the scan of the linear scale 70.
  • the image signal from the detector 7 is sampled in synchronism with the clock signal from the comparator 67 to form the image of the sample 1.
  • the clock signal By forming the clock signal by using the pattern 72, the image of a relatively wide view field corresponding to the width of the pattern 72 can be formed.
  • the linear scale 70 is rotated around a center O by the actuator 61.
  • the linear scale 70 is rotated until the pattern 73 is positioned on the optical axis, the position thereof is detected by the detection circuit 63 based on the output of the detector 62.
  • the CPU 64 determines the amplitude of the spot vibrating on the linear scale 70 based on prestored data such that the amplitude of the spot is substantially equal to the width of the pattern 73, and controls the actuator 14 through the amplitude control circuit 65.
  • the swing angle of the vibration scanner 5 is reduced and the range of scan of the light spot is reduced to one half of that for the pattern 72.
  • the range of scan of the light irradiated to the sample 1 is also reduced to one half. Since the number of gratings of the pattern is same even if the range of scan is reduced to one half, the number of clock signals from the comparator 67 does not decrease. In this manner, a double size enlarged image is formed and the sample can be observed at a high resolution.
  • Figs. 14 and 15 show modifications of the linear scale.
  • a linear scale 80 of Fig. 14 has four patterns 82 to 85 formed perpendicularly to the direction of movement of the light spot SP (the direction of an arrow 86). Assuming that the pitch of the grating of the pattern 82 is 1, the patterns 83 to 85 have stepwise pitches of 1/2, 1/4 and 1/8, respectively.
  • a linear scale 90 of Fig. 15 has a pattern 91 having a continuously varying pitch formed perpendicularly to the direction of movement of the light spot SP (the direction of an arrow 96).
  • the pitch of the grating at a lower end of the pattern 91 is 1/8 of that at an upper end, and the width of the pattern in the scan direction is also reduced to 1/8.
  • control circuit 11 of the first embodiment may be used in place of the amplitude control elements 62 to 65 to attain the automatic change of the amplitude in response to the replacement of the linear scale.
  • the patterns on the linear scale may have the same pitch of the grating with the difference in only the width.
  • the number of clock signals produced by the comparator 67 derived from the narrow pattern is smaller than that derived from the wide pattern.
  • the clock signal may be frequency-multiplied in the same manner as that of the second embodiment to produce the required number of video clock signals.

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  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Mechanical Optical Scanning Systems (AREA)
EP92310037A 1991-11-07 1992-11-02 Générateur d'horloge vidéo pour dispositif de balayage optique d'image Expired - Lifetime EP0541321B1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP96113812A EP0748098A3 (fr) 1991-11-07 1992-11-02 Générateur d'horloge vidéo pour dispositif de balayage optique d'image

Applications Claiming Priority (6)

Application Number Priority Date Filing Date Title
JP3291723A JPH05127109A (ja) 1991-11-07 1991-11-07 振動光学要素の振幅制御装置および制御方法
JP03291724A JP3111551B2 (ja) 1991-11-07 1991-11-07 ビデオクロック信号発生装置
JP291724/91 1991-11-07
JP291723/91 1991-11-07
JP3295944A JPH05136954A (ja) 1991-11-12 1991-11-12 ビデオクロツク信号発生装置
JP295944/91 1991-11-12

Related Child Applications (1)

Application Number Title Priority Date Filing Date
EP96113812A Division EP0748098A3 (fr) 1991-11-07 1992-11-02 Générateur d'horloge vidéo pour dispositif de balayage optique d'image

Publications (3)

Publication Number Publication Date
EP0541321A2 true EP0541321A2 (fr) 1993-05-12
EP0541321A3 EP0541321A3 (en) 1993-08-25
EP0541321B1 EP0541321B1 (fr) 1999-03-10

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Family Applications (2)

Application Number Title Priority Date Filing Date
EP92310037A Expired - Lifetime EP0541321B1 (fr) 1991-11-07 1992-11-02 Générateur d'horloge vidéo pour dispositif de balayage optique d'image
EP96113812A Withdrawn EP0748098A3 (fr) 1991-11-07 1992-11-02 Générateur d'horloge vidéo pour dispositif de balayage optique d'image

Family Applications After (1)

Application Number Title Priority Date Filing Date
EP96113812A Withdrawn EP0748098A3 (fr) 1991-11-07 1992-11-02 Générateur d'horloge vidéo pour dispositif de balayage optique d'image

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EP (2) EP0541321B1 (fr)
DE (1) DE69228583T2 (fr)

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4044248A (en) * 1972-05-03 1977-08-23 Eastman Kodak Company Method and apparatus for linearizing a mirror galvanometer
JPS54160117A (en) * 1978-06-09 1979-12-18 Toshiba Corp Optical scanner
JPS56104571A (en) * 1980-01-24 1981-08-20 Canon Inc Picture output device
EP0147835A2 (fr) * 1983-12-28 1985-07-10 Fuji Photo Film Co., Ltd. Appareil d'analyse à faisceau lumineux
US4584612A (en) * 1984-02-21 1986-04-22 Dainippon Screen Seizo Kabushiki Kaisha Picture recording method
US4661699A (en) * 1983-03-28 1987-04-28 T. R. Whitney Corporation Scanning beam control system and method with bi-directional reference scale
US4761660A (en) * 1986-12-15 1988-08-02 Minnesota Mining And Manufacturing Company Laser scanning apparatus using a fan style grating plate
EP0357190A2 (fr) * 1988-08-30 1990-03-07 Kabushiki Kaisha TEC Balayeur optique
US4962431A (en) * 1987-05-08 1990-10-09 Ricoh Company, Ltd. Synchronizing signal generating system for laser scanner

Family Cites Families (1)

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Publication number Priority date Publication date Assignee Title
US4600951A (en) * 1983-12-20 1986-07-15 At&T Technologies, Inc. Scanning sample, signal generation, data digitizing and retiming system

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4044248A (en) * 1972-05-03 1977-08-23 Eastman Kodak Company Method and apparatus for linearizing a mirror galvanometer
JPS54160117A (en) * 1978-06-09 1979-12-18 Toshiba Corp Optical scanner
JPS56104571A (en) * 1980-01-24 1981-08-20 Canon Inc Picture output device
US4661699A (en) * 1983-03-28 1987-04-28 T. R. Whitney Corporation Scanning beam control system and method with bi-directional reference scale
EP0147835A2 (fr) * 1983-12-28 1985-07-10 Fuji Photo Film Co., Ltd. Appareil d'analyse à faisceau lumineux
US4584612A (en) * 1984-02-21 1986-04-22 Dainippon Screen Seizo Kabushiki Kaisha Picture recording method
US4761660A (en) * 1986-12-15 1988-08-02 Minnesota Mining And Manufacturing Company Laser scanning apparatus using a fan style grating plate
US4962431A (en) * 1987-05-08 1990-10-09 Ricoh Company, Ltd. Synchronizing signal generating system for laser scanner
EP0357190A2 (fr) * 1988-08-30 1990-03-07 Kabushiki Kaisha TEC Balayeur optique

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN vol. 4, no. 21 (E-172)21 February 1980 & JP-A-54 160 117 ( TOSHIBA CORP. ) 18 December 1979 *
PATENT ABSTRACTS OF JAPAN vol. 5, no. 179 (E-82)17 November 1981 & JP-A-56 104 571 ( CANON INC. ) 20 August 1981 *

Also Published As

Publication number Publication date
EP0541321B1 (fr) 1999-03-10
EP0748098A2 (fr) 1996-12-11
EP0541321A3 (en) 1993-08-25
DE69228583T2 (de) 1999-07-01
EP0748098A3 (fr) 1997-03-12
DE69228583D1 (de) 1999-04-15

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